The search for microfossils is sometimes a very unrewarding task. I have collected, washed, and scoured through, quite literally, tons of rock looking for a single mammal tooth. But however tedious and arduous the task of looking for microfossils is, the rewards greatly outweigh the time spent looking. Microfossils are, as you may have guessed, very small fossils. These small fossils can be anything from microscopic animals that lived in water environments to very small bone fragments to very, very small teeth and everything in between. In this case I am referring to very small mammal teeth. These teeth are so small they can be glued on the head of a pin.

The recovery process of these teeth begins with collecting rock. However, paleontologists don’t just randomly stick a shovel in the ground and hope to hit pay dirt. Sites used to study microfossils are chosen very carefully. These sites, called microsites, are usually places where other fossils are already weathering out at the surface. Small fossils, easily visible with the naked eye, are usually common, and the fossils tend to be concentrated within a definable, thin horizon.

This is an example of a thin fossiliferous horizon. The black specks in the overturned chunk are fish scales.

This horizon is then collected by hand or by shovel and brought back to the laboratory. That collected rock is then subjected to a process called screen washing. The collected dirt is washed through one or sometimes two sets of screen, the smallest screen usually smaller than the screen on your windows and doors at home. What remains on the screens after washing is dried and then systematically “picked”- under a microscope where microfossils are collected from the remaining dirt and rock.

The most common fossils that come out of this concentrate are usually fish bones and teeth. Rarely though, a mammal tooth will be found. It is these rare mammal teeth that can potentially tell us the most about one particular site. From being able to potentially restrict the age of the site to within a few million years or to give us greater detail about the paleoenvironment, fossil mammals play an important role in paleontology.

Deep within the bowels of the Heritage Center in Bismarck is a room with great riches. It contains items of staggering age and scientific value. This room contains the North Dakota State Fossil Collection. From giant swimming lizards to “trumpeting” mastodons, from specimens mounted on pins to those needing forklifts to move, the North Dakota State Fossil Collection contains a wealth and variety of specimens (fig. 1). It has been twenty years since the State Fossil Collection was created in 1989 and it has grown in leaps and bounds since then.

This image shows only a small variety of fossils found in the North Dakota State Fossil Collection.

North Dakota Geological Survey (NDGS) geologists had been picking up fossils during the course of their fieldwork since the inception of the Survey in 1895. Those specimens were typically incorporated into the geology department collection. Prior to 1981, the only fossil collections in North Dakota were teaching and research collections at the universities made by faculty, students, and amateur collectors. However, in 1981 Dr. John Hoganson was hired by the NDGS. At that time the NDGS began what is now referred to as the Fossil Resource Management Program, and the recovery of fossils by the NDGS began in earnest. Although not yet officially the “State Fossil Collection,” between 1981 and 1989 North Dakota’s “fossil collection” grew to a small accumulation (a few hundred specimens) of fossil vertebrates and invertebrates. When the main office of the Geological Survey was moved from Grand Forks to Bismarck in 1989, this small collection only required a few cabinets for storage space.

Over the last 20 years, the State Fossil Collection has grown exponentially and now contains approximately 6,100 cataloged specimens (with more being added all the time) and 3,800 fossil localities. It is difficult to give even a rough estimate of how many cataloged and uncataloged specimens are in the State Fossil Collection at this time. The collection now contains plant, invertebrate and vertebrate fossils, and also contains a large rock and mineral collection. After nearly 10 years in the Johnsrud Paleontology Laboratory under the auditorium, it was obvious that we had again outgrown our space. In 2009 the state legislators saw the need to expand the North Dakota Heritage Center and signed a bill allocating money to put a new addition on the current building. Over the years the collection has moved from Grand Forks to Bismarck, and then within Bismarck it has moved twice. With each move the storage space for collections has nearly tripled in size (fig. 2).

Size comparison between North Dakota Heritage Center lab and collection spaces. A) Lab and collection space used between 1991 and 2000. B) Lab and collection space used between 2000 and 2014. C) Lab and collection space currently in use since May 2014.

Although the state collection is very young (some of the older collections in the United States have been around for more than 100 years), we have a very important representation of Cretaceous, Paleocene, and Oligocene fossils not found in very many other museums across the country. This is something we are trying to expand on during every field season. Although many don’t know it, as you walk through the new Adaptation Gallery: Geologic Time, there are great riches just below your feet.

Moving priceless objects can be daunting. Depending on the object, simply moving a rare or priceless object from one table to another or even shifting it a few inches or feet can be stressful. Moving thousands of priceless objects over 300 feet is even more daunting; moving priceless objects under a time schedule, even more so; moving priceless objects under a time schedule, through a construction zone, even more yet. However, with proper planning it can be done.

In the early days of planning the Heritage Center expansion it was quickly discovered that the State Fossil Collection was potentially in harm’s way with all the construction going on in and around the building. Not necessarily from a large piece of machinery or debris, but instead from possible exposure to the elements of nature (water and steeply fluctuating temperatures and humidity levels). Both of these elements can wreak havoc on fossils if not properly prepared for. After all the pros and cons of keeping the collection where it was versus moving the collection to an offsite storage facility were weighed and debated, the decision was made to keep the collection in place and protect the collection from any foreseen hazards to the best of our ability.

In this case water was our main concern. A minor concern was vibration from nearby heavy machinery. To protect the fossils from vibration, foam was placed in drawers and between fossils, cradling each fossil (figs. 1 & 2). To protect it from dripping water, the collection was completely covered in plastic sheeting (fig. 3 & 4). Fossils were also removed from the first 12 inches above the floor in case the storage room should flood. The storage room was heavily monitored for any sign of problems over the next few months. Meanwhile a new storage room was being completed and filled with new, state of the art cabinets and storage compactors to house the important collection (fig. 5).

Finally moving day arrived. Due to all the things needing to be done our window to move the collection was small. A team of paleontologists and skilled volunteers moved thousands of fossils over the course of a few days, reorganizing the collection as we moved it.

The project has been completed and the collection receives routine and ongoing maintenance and organization.

Fig. 1 – Paleontologist Amanda Person (left) and paleo intern Samantha Pounds (right) placing foam padding between fossils.

Fig. 2 – Paleontologists Becky Barnes (left) and Amanda Person (right) placing foam padding between fossils.

Fig. 3 – Paleontologist Becky Barnes securing plastic sheeting on top of metal cases containing the ND State Fossil Collection.

Fig. 4 (left) – Metal cabinets containing ND State Fossil Collection covered in plastic to protect from possible water damage.
Fig. 5 (right) – The new cabinets holding the important ND State Fossil Collection.